It is the purpose of this invention to provide a unique distribution groove for a balanced flow passage used to disperse the molten plastic in an extrusion die evenly within an annular extrusion channel. Die systems, employing balanced flow distribution grooves, are constructed by assembling a series of cylindrical components along a common axis. A continuous flow passage is formed by the cooperation of the adjacent components. The passage may comprise an inlet, a pair of flow channels, a distribution groove, a conical extrusion channel, and an outlet which sequentially communicate to form a continuous passage. It is the purpose of this invention to provide components which have multiple applications and to facilitate the replacement of certain parts of the passage to provide different functions.